Valve body

ABSTRACT

The invention relates to a valve, comprising a valve body for controlling a medium flowing through the valve, a valve housing ( 3 ), in which the valve body ( 1 ), which has at least one gasket ( 4 ) for sealing cooperation with the valve housing ( 3 ) or where appropriate with a cage ( 5 ) arranged in the valve housing, is axially displaceable by a spindle ( 6 ) in the direction towards and from a valve seating ( 7 ) in the valve. The gasket ( 4 ) extends peripherally around the circumference of the valve body ( 1 ) and is expandable in the radial direction to tight abutment against the valve housing ( 3 ) or the cage ( 5 ) arranged in the latter through axial pressing of at least one press member ( 9 ′) acting on the gasket ( 4 ) when the valve body ( 1 ) is just before and/or in its closing position.

The present invention relates to a valve body for controlling a mediumflowing through a valve, which valve comprises a valve housing, in whichthe valve body, which has at least one gasket for sealing cooperationwith the valve housing or where appropriate with a cage arranged in thevalve housing, is axially displaceable by means of a spindle in thedirection towards and from a valve seating in the valve.

For certain valve applications currently on the market it is required bythe person using these that the valve should be tight, which normallygives a unidirectional very strong setting force. To achieve as weaksetting force as possible one uses a so called balanced valve, which isachieved by a connection channel extending between the low pressure sideof the valve body and the confined volume, which is above the valve bodyand within the valve lid. Up to now, these two mentioned variants ofvalve applications have not been possible to combine completely.

The object of the present invention, therefore, is to provide a tightvalve body and more particularly a balanced, tight valve body, whichconsists of a complete valve package, in which the components of thevalve body completely seal, when the valve body is just before and/or inits closing position in the valve housing at the same time as such asmall frictional wearing as possible arises on the gasket, when thevalve is working outside its closing positions. The characterizingfeatures of the invention are stated in the accompanying claims.

Thanks to the invention a new type of valve body for controlling amedium of the above mentioned kind flowing through a valve, which valvebody in an excellent manner fulfills its purposes and in addition at thesame time is simple and cheap to manufacture. The valve body accordingto the invention specifically has a press member, preferably In the formof a sleeve, which runs externally on a central valve cone, and a gasketmade of a material that when influenced by forces from the sleeve canexpand radially outwardly as well as inwardly. In a preferred embodimentthe gasket is fixable in its position with the aid of a split ring,which is axially locked through assemblage in a groove in the valvecone. Thanks to this solution, when the valve cone reaches its closingposition against the valve seating it results in that the sleeve slideson the valve cone and transfers forces against and compresses thegasket, which then expands radially in its space defined by the sleeve,the split ring, the valve cone and the wall present within the valve.The gasket in question creates a strong surface pressure on the surfacesdefining the closed volume.

In the opened valve position when the valve is in operation the sleeveis no longer in contact with the valve seating, wherein the sleeve nolonger transfers any forces that influences the gasket and will notcreate any surface pressures at its confining surfaces as well. Byeliminating or delimiting the surface pressure against the gasket, thefriction against the present valve wall, towards which the valve bodyruns, will be very low, wherein also the required setting force of thevalve can be kept low at the same time as the wear of for example thegasket is radically reduced. By the structure in question only one forceagainst the gasket is created when the valve is closed whereas when thevalve is open and working this force against the gasket has beencompletely eliminated, wherein no frictional forces can be generated atthe same time as the structure in question compensates the wear of thegasket through the axial movement of the sleeve.

The invention is described in more detail below with the aid of somepreferred embodiments with reference to the accompanying drawings, inwhich

FIG. 1 schematically shows a cross sectional view through a valve bodyaccording to the invention and according to a first embodiment,

FIG. 2 schematically shows a cross sectional view through a completevalve with a valve cone according to FIG. 1 mounted therein,

FIG. 3 shows an alternative embodiment of a valve body designedaccording to a second embodiment and

FIG. 4 shows a further alternative embodiment of a valve bodyillustrated in a cross-section.

As appears in more detail from FIG. 1 there is shown in accordance witha first embodiment a valve body 1 according to the invention, intendedfor mounting in a valve housing 3 of a valve 2, in which the valve body1, which has at least one gasket 4 for sealing cooperation with thevalve housing 3 or where appropriate with a cage 5 arranged in the valvehousing, is displaceable axially by means of a spindle 6 in thedirection towards and from a valve seating 7 in the valve 2. The valvebody 1 according the embodiment shown in FIG. 1 is guided by a spindle6, as mentioned above, In the valve 2 and Is constituted by a valve cone8 with a sleeve 9 enclosing the latter and serving as a press member 9′,which sleeve 9 is displaceably arranged in a recess 10, which in thisembodiment extends almost to the free end 11 of the valve cone 8 tocooperate with a valve seating 7. In the opposite end 12 of the valvecone 8 the sleeve 9 is retained in its recess 10 with the aid of afixing member 14 arranged in a groove 13. Between this fixing member 14and the adjacent rear portion 15 of the sleeve 9 the gasket 4 isarranged, which extends around the circumference of the valve cone 8. Inthe example shown a plane gasket 25 is positioned between the gasket 4and the fixing member 14 to prevent the gasket 4 from being squeezed inthe slots that can be formed when the fixing member 14 is constituted bya split ring. To prevent rotation between the sleeve 9 and the valvecone 8 there is a rotational pin 26. The function of the sleeve 9 on thevalve cone 8 is to compress the gasket 4 when the sleeve 9 moves towardsthe gasket 4, which occurs when the valve body 1 is just before and/orin its closing position, so that the gasket 4 expands in its spacedefined by the sleeve 9, the fixing member 14 with its possible planegasket 25, the valve cone 8 and the present valve housing wall. As aresult, the gasket 4 creates a strong surface pressure on all of itsconfining surfaces.

In an open valve position, i.e. when the valve 2 is in operation, thesleeve 9 is no longer in contact with the valve seating 7, wherein thesleeve 9 no longer can transfer any force that influences the gasket 4.Then, the sleeve 9 will not create any surface pressure on its confiningsurfaces and in particular the gasket 4, as well. By eliminating ordelimiting the surface pressure of the gasket 4 the friction against thevalve housing 3 or where appropriate against the cage 5 arranged in thevalve housing will be very low, wherein also the required setting forceof the valve 2 can be kept very low at the same time as the wear,especially of the gasket 4, can be radically reduced. In the exampleshown according to FIG. 1 the fixing member 14 is situated in a groove13 in the valve cone 8 and in the present case is designed as a splitring, which automatically is kept together when the valve cone 8 isinserted in the valve 2 or is fixed in position with the aid of alocking ring 16. The gasket 4 may be made of an elastic material, forexample consisting of a plastic or metallic material and preferably ofgraphite.

As shown in more detail in FIG. 2 the valve body 1 in this case ismounted in a valve 2, which in turn houses a cage 5 arranged in thevalve housing 3. The valve body 1 is displaceable arranged in said cage5 and the gasket is situated in the rear end 12 of the valve cone 8 atthe same time as its front free end 11 is cooperable with a valveseating 7 situated in the valve 2. To give a greater effect of thesealing 4 when it expands in the radial direction the abutting surface17 of the gasket 4 against the corresponding surface 18 on the sleeve 9serving as a press member 9′ is angled or oblique. In the example shownwhere the valve cone 8 is arranged in a cage 5 the latter as a pluralityof holes 19, which are uncovered when the valve body 1 is displaced fromits closed position to its open position.

In FIG. 3 there is shown an alternative embodiment of a valve body 1according the invention in which the front portion 20 of the sleeve 9encloses the front end 11 of the valve body and is journalled in theaxial direction on a pin 21 centrally protruding from the front free end11 of the valve body 1. In this example the sleeve 9 generally isdesigned as a hat instead of ending a short distance before the free end11 of the valve cone 8, as in the previous embodiment.

In FIG. 4 there is finally shown a further embodiment of the valve body1 according to the invention in which generally the entire valve cone 8is designed as a press member movable in the axial direction and isdisplaceable fixed in position in a sleeve 22 provided with a flange onthe spindle 6, which sleeve 22 forms a peripheral shoulder 23 for thegasket 4, which is arranged between this stationary shoulder 23 and amovable shoulder 24 on the press member 9′ and between which the gasket4 is contractible for its radial expansion.

What is claimed is:
 1. A valve (2), comprising a valve body forcontrolling a medium flowing through the valve (2), a valve housing (3),in which the valve body (1), which has at least one gasket (4) forsealing cooperation with the valve housing (3) or where appropriate witha cage (5) arranged in the valve housing, is axially displaceable bymeans of a spindle (6) in the direction towards and from a valve seating(7) in the valve, characterized in that the gasket (4) extendsperipherally around the circumference of the valve body (1) and isexpandable in the radial direction to tight abutment against the valvehousing (3) or the cage (5) arranged in the latter by axial pressure ofat least one press member (9′) acting on the gasket (4), when the valvebody (1) is just before and/or in its closing position, which pressmember (9′) is constituted by a sleeve (9) extending around the valvebody (1), which sleeve (9) transfers a compression force against thegasket (4) when the valve cone (8) reaches its closing position againstthe valve seating (7) resulting in the radial expansion of the gasket(4), the gasket (4) having an angled or oblique abutment surface (17)for cooperation with a corresponding surface (18) on the press member(9′).
 2. A valve according to claim 1, characterized in that the sleeve(9) extends around the valve cone (8) to the free end (11) thereof withits front portion (20) for cooperation with the valve seating (7) at thesame time as the opposite rear portion (15) of the sleeve (9) extends tothe gasket (4) and which parts together are fixed in position side byside of each other within a predetermined displacement distance, whichgenerally corresponds to the contractibility of the gasket (4) on thevalve cone (8) in the axial direction through a fixing member (14),which in turn is fixed in the rear end (12) of the valve cone (8) in agroove (13).
 3. A valve according to claim 2, characterized in that thesleeve (9) has an axial extension on the valve cone (8) that ends justbefore its front free end (11) and is displaceable together with thegasket (4) a short distance on the mantle surface of the valve cone (8).4. A valve according to claim 2, characterized in that the front portion(20) of the sleeve (9) encloses the valve body and is journalled in theaxial direction on a pin (21) centrally protruding from the front freeend (11) of the valve body (1).
 5. A valve according to claim 1,characterized in that the gasket (4) is arranged to slide without anygreater friction against the valve housing (3) or the cage (5) arrangedin the latter, when the valve (2) is in an open position, i.e. as longas the press member (9′) is not in contact with the valve seating (7).6. A valve according to claim 1, characterized in that the press member(9′) is designed as a valve cone and is movably fixed in position in asleeve (22) provided with a flange on the spindle (6), which sleeve (22)forms a peripheral shoulder (23) for the gasket (4), which is situatedbetween this rigid shoulder (23) and a movable shoulder (24) existing onthe press member (9′), between which the gasket (4) is contractible forits radial expansion.